I think I know the answer to this question, but once again I will ask experts.

2009 Hyundai Accent, just under 17k. Four days ago I had a nail removed from one of my tires and they patched the hole. This afternoon as I am leaving from work I notice the TPMS indicator light has come on as I am driving. As experts recommend elsewhere here I checked my owners manual but it says take it to the dealer. I should, however, be able to take it back to the shop and have them check it, correct?

Also, this is not something that I will have to take care of like right now, as my tires are not flat (I am going to check the pressure in all, including the spare, as a precaution, in a bit), as the system is just a monitoring device, right?

Just for monitoring. If you check with a gauge and all is good then you have a sensor issue. Better off going back to who di the repair. The sensor is fairly large in the tire, part of valve stem assembly maybe it got damaged during repair.

My wife’s 06 Toyota Sienna has a passive TPMS system that uses the ABS system. I think the principle is that a tire with low pressure rotates at a different speed from a fully inflated tire. The TPMS senses this and turns on the warning light.

My 2010 Cobalt has a pressure sensor in each tire to directly measure the tire pressure.

Both systems have to be reset after a tire repair, replacement, or rotation. The Sienna has a button to reset the system. The Cobalt has to relearn each tire in a rather complicated procedure.

For now check each tire with a good quality dial type gauge, it’s difficult to tell if a tire has enough pressure from a visual check. Don’t assume the repair shop is going to set the correct pressure.

I would check the Owner’s manual again, it took a while to find the reset procedure for the Sienna (+500 page manual).

Ed B.

TPMS. If it works, fine. If it does not work, black tape. Or you could spend half a day at the dealers shop while they fiddle with it…